When comparing Iris Light vs Zukitre, the Slant community recommends Zukitre for most people. In the question“What are the best gtk3 themes?” Zukitre is ranked 9th while Iris Light is ranked 25th. The most important reason people chose Zukitre is:
The design of Zukitre differs from Zukitwo in that there are fewer gradients and rounded corners. It is also designed to be more flat.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Multi GTK support
Iris supports newer versions of GTK3 (3.10) and also GTK2.
Pro Designed to be flat with sharp corners
The design of Zukitre differs from Zukitwo in that there are fewer gradients and rounded corners. It is also designed to be more flat.
Cons
Con Development not finished
Iris is still in beta so there may still be bugs and other glitches.
Con Only supports the latest release of Gnome Shell and GTK
For Debian or Ubuntu users this theme will not work as it only supports the latest version of Gnome Shell and GTK.